DKK1 and pancreatic serous cystadenoma: Of the total 356 CCC patients, 95 patients were able to identify the etiology, and they were classified into sporadic (n = 75), hepatitis B virus (HBV) (n = 5), hepatitis C virus (HCV) (n = 1), liver fluke (n = 1), liver cirrhosis (n = 6), PSC (n = 0), and bile duct stone (n = 7), respectively, and their median level of DKK-1 and CA 19-9 are described in Table S1.